We (Francesco Siddi and myself) have just released the render queuing system brender as open-source project. It was first written in 2005 when I needed a simple render queuing system built around blender. The system is an apache/php/mysql server running a script and dispatching the different render orders to client machines. There is a web interface for managing the projects, job, clients and orders. It has a slightly more complicated setup time (due to some paths possible confusion) because it allows scene files (and all the dependencies) to be on any machine in the local network, not necessarly on the server.
you can check a simple video for an overview of it :
We are looking for people interested in trying it out and giving some feedback. The project is hosted on github and you can find a download page here : http://oenvoyage.github.com/brender/